WO2012156616A1 - Process and device for limiting the emission of gaseous pollutants from anode butts - Google Patents

Process and device for limiting the emission of gaseous pollutants from anode butts Download PDF

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Publication number
WO2012156616A1
WO2012156616A1 PCT/FR2012/051014 FR2012051014W WO2012156616A1 WO 2012156616 A1 WO2012156616 A1 WO 2012156616A1 FR 2012051014 W FR2012051014 W FR 2012051014W WO 2012156616 A1 WO2012156616 A1 WO 2012156616A1
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WO
WIPO (PCT)
Prior art keywords
alumina
butt
anode
tray
butts
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PCT/FR2012/051014
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French (fr)
Inventor
Thierry Malard
Florent GAUTIER
Antoine De Gromard
Original Assignee
Solios Environnement
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Publication date
Application filed by Solios Environnement filed Critical Solios Environnement
Priority to CA2835800A priority Critical patent/CA2835800C/en
Priority to EP12725115.5A priority patent/EP2710170B1/en
Priority to CN201280021816.1A priority patent/CN103597125B/en
Publication of WO2012156616A1 publication Critical patent/WO2012156616A1/en

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
    • C25C3/12—Anodes
    • C25C3/125—Anodes based on carbon

Definitions

  • the present invention relates to the reduction of gaseous effluents emitted during the industrial production of aluminum by igneous electrolysis.
  • BACKGROUND OF THE INVENTION The present invention relates to the reduction of gaseous effluents emitted during the industrial production of aluminum by igneous electrolysis. This production is carried out in tanks grouped by several tens in an electrolysis hall called "potroom”. Each vat comprises consumable preformed anodes and a fixed cathode in order to carry out the reduction reaction of aluminum alumina which is deposited at the bottom of said vat. This reaction takes place at a temperature above 950 ° C. and in the presence of fluorine.
  • anode butt the lower part of the anode which was below the level of the blanket alumina in the electrolytic cell.
  • the anode butt thus comprises the remaining carbon part, a part of the metal element on which it is fixed and fluorinated bath residues and alumina cover whose carbon portion is covered.
  • electrolysis bath residues in contact with the air emit highly pollutant fluorine gas (HF).
  • HF highly pollutant fluorine gas
  • Patent CA221 6923 describes a process in which the effluents emitted by the butts are recovered with the capture device specific to the electrolysis cells. For this, the butts are placed in a closed chamber placed in the immediate vicinity of the tank and connected to the suction device thereof. This process is not entirely satisfactory because it requires delicate handling of butts to place them in their closed enclosure. Moreover, it does not make it possible to limit the effluent emissions by the butts and requires an additional capacity of the fume treatment device of the electrolysis cells to treat the emanations from the butts. Finally, it clogs the vicinity of the electrolysis cell which hinders the work of the operators.
  • Patent CA2256145 describes a process for cooling anode butts and reducing their emission of fluorine gases.
  • the anode butts pass through a covered tunnel by being immersed in a bed of fluidized alumina. Air is injected to ensure fluidization of the alumina and convection cooling of the butts.
  • the butts pass through the tunnel for a period of about 2 hours, which allows their temperature to be lowered below 300 ° C.
  • the cooling then continues in the open air.
  • the fluidized alumina surrounding the butt captures a large part of the fluorinated gases emitted, the balance being taken up by the tunnel ventilation system before being purified by a traditional flue gas treatment device.
  • the butts are placed in containers in which they can be covered with alumina in order to limit emissions of fluorine gas.
  • This technical solution is not fully satisfactory because it requires a tunnel of considerable length, between 25 and 60 meters, requiring significant fluidization rates, as well as means for handling and moving the anodes which are potential source of failures.
  • the tunnel also requires a relatively complex device for injecting air so as to also fluidize the alumina located above the butts.
  • the passage of anode butts in connecting containers requires additional handling operations.
  • the covering of hot anodes with alumina can create a phenomenon of alumina geyser and requires emptying the alumina after each use of the container.
  • the proposed invention makes it possible to limit the emissions of gaseous effluents by the anode butts after their removal from the electrolysis cells, and to capture the emanations produced by a simple device for implementation. It consists in particular, preferably for each anode butt removed from a tank, to isolate the portion of the butt covered with bath residues of the ambient air. For this, the butt is immersed in a volume of alumina powder contained in a tray so that the butt is completely immersed in the alumina. The fluorine gas that may be formed is immediately captured by the alumina, thus avoiding any pollution of the hall.
  • the invention consists in a process for treating anode butts from aluminum production tanks by igneous electrolysis by covering the anode butts with alumina having a fluorine uptake capacity, characterized in that that, as soon as a butt is removed from an electrolytic cell, said butt is immersed in alumina previously fluidized to facilitate the immersion, and in that the fluidization of the alumina is stopped as soon as the end of immersing, so that the butt is covered, with static alumina until the end of its transfer from said electrolytic cell to a station equipped with at least one suction and fume treatment device , in particular a hot crushing station or a cooling station, so as to confine the butt and limit its emission of gaseous pollutants, especially fluorinated.
  • said volume of alumina is fluidized to facilitate the introduction of the still hot anode butt in this volume. Fluidization is cut off as soon as the butt is in place. After stopping the fluidization, the alumina falls by gravity and covers the anode butt leading to confinement thereof. Alumina then acts as a physical barrier, limiting air convection movements around the butt, and chemical barrier since the gaseous fluoride emitted by the butt is immediately adsorbed by the alumina.
  • the alumina is fluidized during removal of the anode butt to facilitate removal.
  • the carbon portion is at a temperature of about 700 ° C when the anode butt is removed from the electrolysis cell. From a temperature of about 300 ° C, the emission of fluorinated gas by the carbon portion becomes low enough that it is no longer necessary to confine it.
  • the alumina After transfer of the anode butt to the hot crushing station equipped with at least one suction and fume treatment device, the alumina is fluidized again to promote removal of the anode butt out of the volume of the anode. alumina wherein said butt has been confined.
  • the carbonaceous part is crushed to be used for the manufacture of new anodes.
  • the carbon elements After the crushing operation, the carbon elements are maintained under at least one suction and treatment device. fumes, at least until their temperature has dropped below 300 ° C.
  • the alumina is again fluidized to promote the cooling of the carbon part of the anode butt. Cooling is advantageously maintained until the temperature of the carbon portion has dropped below 300 ° C.
  • the invention also consists of a device for the treatment of anode butts, making it possible to implement the process described above, characterized in that it comprises at least one tank containing alumina in an amount sufficient to cover the butt anode and a fluidization means of this alumina.
  • - Fig.1 is a schematic perspective view of an anode consumed
  • - Fig. 2 is a diagrammatic perspective view of an exemplary embodiment of the butt receptacle according to the invention
  • FIG. 3 is a diagrammatic view in vertical section of a cigarette butt receptacle according to the invention.
  • FIG. 4 is a schematic view of a cigarette butt receptacle according to the invention placed at a station equipped with a device for suction and treatment of fumes.
  • Figure 1 shows a schematic view of a consumed simple anode, standard for the production of aluminum by igneous electrolysis. It is composed of a carbon part 1 hooked to a metal rod 2, 2 to 3 m long, and serving for the supply of electric current and the attachment to the electrolysis cell. Upon removal from the electrolytic cell, a layer of residual cover alumina 1 2 remains above the carbon portion 1 and covers a portion of the metal rod 2.
  • the anode butt 5 is composed of the part 1, residual cover alumina 1 2 and part of the metal rod 2 which is covered by the residual cover alumina 1 2.
  • the receptacles 3 with butts are composed of a metal structure defining trays 4a, 4b, 4c inside which are deposited the anode butts 5.
  • the receptacle 3 is composed of 3 trays and can therefore accommodate three double anode butts such as 5.
  • the receptacles 3 will have a different number of bins, for example 2 or 4.
  • each tray 4 comprises a plate 6 of a material for retaining alumina 8 while having sufficient porosity to act as a fluidizing fabric.
  • This plate 6 may, for example, be a metal sinter. It is supported by reinforcements not shown in this figure.
  • the zone 7 under the metal sintered plate 6 is supplied with fluidization gas in order to ensure the fluidization of the alumina 8.
  • the fluidization gas is advantageously air but may be of a different nature, for example nitrogen.
  • the fluidization gas supply device of zone 7 is not shown in the figures.
  • the metal sintered plate 6 and the alumina filler 8 generate a pressure drop which promotes a homogeneous distribution of the gas over the entire surface of the metal sinter plate 6.
  • the fluidization gas supply device may comprise several gas flows so as to distribute the flow rate over different sectors of the surface of the zone. 7.
  • FIG. 2 are shown the three situations in which a tray 4 may be.
  • the tray 4a is empty, without alumina
  • the tray 4b is filled with fluidized alumina 8a
  • the tray 4c contains an anode butt 5 confined in a volume of non-fluidized alumina 8b.
  • all the tanks 4 is filled with alumina 8.
  • the fluidization of the alumina 8 is advantageously controlled individually, tray 4 per tray, so as to limit this state to the tray 4 where the fluidization is necessary.
  • two crosspieces 9 serve as abutments or spacers between the anode butt 5 and the plate 6.
  • the crosspieces 9 are placed a few centimeters above the metal sintered plate 6, for example 1 0 cm.
  • the number, shape and dimensions of these sleepers 9 are chosen so as not to increase the pressure drops for the fluidizing gas and to allow access to the operators for the emptying and cleaning operations of the bins 4.
  • the sleepers 9 may be made of I-beam or T-shaped section.
  • the sleepers 9 are for example fixed by their longitudinal ends on two opposite vertical walls of the metal structure 3. They may also rest on the plate 6 if a load recovery is provided below the plate 6.
  • the anode rod 2 can be stabilized by means of removable fasteners 1 0. These are for example fixed between the edge of the metal structure 3 and the rod 2 of the anode.
  • the amount of alumina 8 needed per tray 4 is about 1.8 m 3 .
  • the dimensions of the tanks 4 are defined by the dimensions of the carbon portion 1 of the butts 5 and the volume of alumina 8 required.
  • the bins 4 have for example a length of 2 m, a width of 2 m and a height of 1 m.
  • the height of alumina 8 before immersion of the butt is about 0.6 m.
  • the feed of the tanks 4 in fluidization gas can be carried out by various means, for example by connecting to the fluidization air network of the electrolysis tanks.
  • a specific air network can also be realized for the fluidization of the bins 4 for the entire potroom.
  • each receptacle 3 can be equipped a fan delivering the necessary air flow to the receptacle.
  • the flow rate and supply pressure of the alumina fluidization air are adjusted during commissioning of the plant. For example, a tank 4 is fed with a flow rate of about 270 m 3 / h under a pressure of about 1500 daPa.
  • the alumina 8 used does not need to have a very high capture power. It serves primarily as a physical barrier to prevent convection of air around the anode. Thus, fluorinated alumina 8 used in the electrolytic tanks can be used in the tanks 4. Alternatively, pure, non-fluorinated alumina 8 can be used.
  • a pile of alumina can remain in place on top of the carbonaceous part 1. Part of this alumina is likely to fall on the ground during the displacement of the butt 5.
  • the operator can hunt this alumina by means of a tool manual or a gas jet.
  • lateral nozzles may be placed in the upper part of the tray 4 to carry out this operation automatically during removal of the butt 5.
  • the receptacles 3 butts include means to be supported for example by a forked vehicle or a crane.
  • a forked vehicle or a crane it is possible to move the receptacles 3 in a space in the vicinity of the potroom, in which will be performed for example the cooling of the butts 5 or crushing them.
  • a potroom includes 1 or 2 parallel rows of electrolysis tanks.
  • the anode replacement operations are carried out along the potroom. It is therefore appropriate to place a receptacle 3 comprising three trays 4 butts 5 every three tanks in any row at the same time as are disposed the new anodes ready tanks.
  • a receptacle 3 comprising three trays 4 butts 5 every three tanks in any row at the same time as are disposed the new anodes ready tanks.
  • alumina 8 It is necessary to periodically renew the alumina 8 contained in the tanks 4 so as to maintain sufficient captation capacity.
  • the fluidization of alumina 8 at each removal and removal operation of butt 5 makes it possible to ensure mixing of the alumina 8 and thus a homogeneous fluorine enrichment of the whole of the tank 4.
  • the emptying frequency is linked to the quality of alumina used. The higher the initial capture capacity of alumina 8 will be important and more emptied can be spaced.
  • the use of pure, non-fluorinated alumina in place of the alumina intended for the tanks makes it possible to renew the tanks 4 less frequently. It is advantageous to organize a periodic emptying at a defined frequency or occasionally the evacuation of electrolysis bath waste.
  • the emptying of the tanks 4 will advantageously be performed after the transfer of the receptacles 3 to a suitable space.
  • Each tank 4 of the device according to the invention comprises one or more emptying hatches placed just above the metal sinter plate 6. It is advantageous to fluidize the alumina during the emptying so as to facilitate its evacuation.
  • the fluidizing plate or fabric 6 is strong enough for an operator to enter the butt receptacle 3 to remove anode butt fragments fallen on the bottom.
  • FIG. 4 is schematically represented a receptacle 3 with butts 5 according to the invention, placed at a station 1 1 equipped with devices 13 for suction and treatment of fumes.
  • This station 11 may be in particular a hot crushing station or an anode butt cooling station 5.

Abstract

The invention relates to a process and device for treating anode butts (5), taken from cells for producing aluminium by melt electrolysis, by covering the anode butts (5) with alumina (8) that is able to capture fluorine, the process consisting in, as soon as the butt (5) has been removed from the electrolysis cell, submerging it in alumina (8) that has been melted beforehand in order to make the submersion easier, and in that the alumina is allowed to solidify after the submersion so that the butt is covered with solid alumina until it has made the transfer from the electrolysis cell to a station equipped with devices for extracting and treating fumes, especially a hot grinding station or a cooling station, so as to confine the part and limit emission of gaseous pollutants, especially fluorinated pollutants.

Description

PROCEDE ET DISPOSITI F POUR LIMITER LES EMISSIONS DE POLLUANTS GAZEUX PAR LES MEGOTS D'ANODE La présente invention concerne la réduction des effluents gazeux émis lors de la production industrielle d'aluminium par électrolyse ignée. Cette production est réalisée dans des cuves regroupées par plusieurs dizaines dans une halle d'électrolyse appelée « potroom ». Chaque cuve comprend des anodes précuites consommables et une cathode fixe afin de réaliser la réaction de réduction de l'alumine en aluminium qui vient se déposer au fond de ladite cuve. Cette réaction a lieu à une température supérieure à 950 °C et en présence de fluor.  The present invention relates to the reduction of gaseous effluents emitted during the industrial production of aluminum by igneous electrolysis. BACKGROUND OF THE INVENTION The present invention relates to the reduction of gaseous effluents emitted during the industrial production of aluminum by igneous electrolysis. This production is carried out in tanks grouped by several tens in an electrolysis hall called "potroom". Each vat comprises consumable preformed anodes and a fixed cathode in order to carry out the reduction reaction of aluminum alumina which is deposited at the bottom of said vat. This reaction takes place at a temperature above 950 ° C. and in the presence of fluorine.
Lorsque les anodes sont consumées, elles sont retirées de la cuve par un pont roulant et sont généralement déposées à l'intérieur de la halle d'électrolyse, le temps qu'elles refroidissent. Dans la suite de ce document, nous appelons mégot d'anode, la partie inférieure de l'anode qui se trouvait en dessous du niveau de l'alumine de couverture dans la cuve d'électrolyse. Le mégot d'anode comprend donc la partie carbonée restante, une partie de l'élément métallique sur lequel celle-ci est fixée ainsi que des résidus de bain fluorés et d'alumine de couverture dont la partie carbonée est recouverte. When the anodes are consumed, they are removed from the tank by a crane and are usually deposited inside the electrolysis hall, the time they cool. In the remainder of this document, we call anode butt, the lower part of the anode which was below the level of the blanket alumina in the electrolytic cell. The anode butt thus comprises the remaining carbon part, a part of the metal element on which it is fixed and fluorinated bath residues and alumina cover whose carbon portion is covered.
Pendant leur refroidissement, tant que leur température est supérieure à environ 300 °C, les résidus de bain d'électrolyse en contact avec l'air émettent du fluor gazeux (HF), très polluant. Le fluor gazeux résulte de la réaction des résidus de bain avec l'eau présente dans l'air sous forme de vapeur. During their cooling, as long as their temperature is above about 300 ° C, electrolysis bath residues in contact with the air emit highly pollutant fluorine gas (HF). The gaseous fluorine results from the reaction of the bath residues with the water present in the air as vapor.
Le brevet CA221 6923 décrit un procédé dans lequel les effluents émis par les mégots sont récupérés avec le dispositif de captage propre aux cuves d'électrolyse. Pour cela, les mégots sont placés dans une enceinte fermée placée au voisinage immédiat de la cuve et reliée au dispositif d'aspiration de celle-ci. Ce procédé n'est pas pleinement satisfaisant car il nécessite une manipulation délicate des mégots pour les placer dans leur enceinte fermée. De plus, il ne permet pas de limiter les émissions d'effluents par les mégots et nécessite une capacité supplémentaire du dispositif de traitement des fumées des cuves d'électrolyse pour traiter les émanations provenant des mégots. Enfin, il encombre le voisinage de la cuve d'électrolyse ce qui gêne le travail des opérateurs. Patent CA221 6923 describes a process in which the effluents emitted by the butts are recovered with the capture device specific to the electrolysis cells. For this, the butts are placed in a closed chamber placed in the immediate vicinity of the tank and connected to the suction device thereof. This process is not entirely satisfactory because it requires delicate handling of butts to place them in their closed enclosure. Moreover, it does not make it possible to limit the effluent emissions by the butts and requires an additional capacity of the fume treatment device of the electrolysis cells to treat the emanations from the butts. Finally, it clogs the vicinity of the electrolysis cell which hinders the work of the operators.
Le brevet CA2256145 décrit un procédé pour le refroidissement de mégots d'anodes et la réduction de leur émission de fluor gazeux. Selon ce procédé, les mégots d'anode traversent un tunnel capoté en étant immergés dans un lit d'alumine fluidisée. De l'air est injecté pour assurer la fluidisation de l'alumine et le refroidissement par convection des mégots. Les mégots traverse le tunnel pendant une durée d'environ 2 heures ce qui permet d'abaisser leur température en dessous de 300 °C. Le refroidissement se poursuit ensuite à l'air libre. Pendant son passage dans le tunnel, l'alumine fluidisée entourant le mégot capte une grande partie des gaz fluorés émis, le solde étant repris par le système de ventilation du tunnel avant d'être épuré par un dispositif traditionnel de traitement des fumées. Pour leur transfert de la cuve d'électrolyse au tunnel de refroidissement, les mégots sont placés dans des containers dans lesquels ils peuvent être recouverts d'alumine afin de limiter les émissions de fluor gazeux. Cette solution technique n'est pas pleinement satisfaisante car elle nécessite un tunnel d'une longueur importante, comprise entre 25 et 60 mètres, nécessitant des débits de fluidisation importants, ainsi que des moyens de manutention et de déplacement des anodes qui sont source potentiel de pannes. Le tunnel requiert également un dispositif relativement complexe d'injection d'air de sorte à fluidiser également l'alumine située au dessus des mégots. Le passage des mégots d'anodes dans des containers de liaison nécessite des opérations de manutention supplémentaires. De plus, tel qu'il est réalisé, le recouvrement des anodes chaudes par de l'alumine peut créer un phénomène de geyser d'alumine et nécessite de vidanger l'alumine après chaque usage du container. L'invention proposée permet de limiter les émanations d'effluents gazeux par les mégots d'anode après leur retrait des cuves d'électrolyse, et de capter les émanations produites par un dispositif simple de mise en œuvre. Elle consiste notamment, de préférence pour chaque mégot d'anode retiré d'une cuve, à isoler la partie du mégot recouverte de résidus de bain de l'air ambiant. Pour cela, le mégot est plongé dans un volume de poudre d'alumine contenu dans un bac de sorte que le mégot soit complètement immergé dans l'alumine. Le fluor gazeux éventuellement formé est immédiatement capté par l'alumine évitant ainsi toute pollution de la halle. Ainsi, l'invention consiste en un procédé de traitement de mégots d'anode provenant de cuves de production d'aluminium par électrolyse ignée en recouvrant les mégots d'anode par de l'alumine ayant un pouvoir de captation du fluor, caractérisé en ce que, dès le retrait d'un mégot d'une cuve d'électrolyse, ledit mégot est immergé dans de l'alumine préalablement fluidisée pour faciliter l'immersion, et en ce que la fluidisation de l'alumine est stoppée dès la fin de l'immersion, de sorte que le mégot soit recouverte, par de l'alumine statique jusqu'à la fin de son transfert de ladite cuve d'électrolyse à un poste équipé d'au moins un dispositif d'aspiration et de traitement des fumées, notamment un poste de concassage à chaud ou un poste de refroidissement, de sorte à confiner le mégot et limiter son émission de polluants gazeux, notamment fluorés. Selon l'invention, ledit volume d'alumine est fluidisé pour faciliter l'introduction du mégot d'anode encore chaud dans ce volume. La fluidisation est coupée dès que le mégot est en place. Après l'arrêt de la fluidisation, l'alumine retombe par gravité et recouvre le mégot d'anode conduisant au confinement de celui-ci. L'alumine joue alors le rôle de barrière physique, en limitant les mouvements de convection d'air autour du mégot, et de barrière chimique puisque le fluor gazeux émis par le mégot est immédiatement adsorbé par l'alumine. Patent CA2256145 describes a process for cooling anode butts and reducing their emission of fluorine gases. According to this method, the anode butts pass through a covered tunnel by being immersed in a bed of fluidized alumina. Air is injected to ensure fluidization of the alumina and convection cooling of the butts. The butts pass through the tunnel for a period of about 2 hours, which allows their temperature to be lowered below 300 ° C. The cooling then continues in the open air. During its passage in the tunnel, the fluidized alumina surrounding the butt captures a large part of the fluorinated gases emitted, the balance being taken up by the tunnel ventilation system before being purified by a traditional flue gas treatment device. For transfer from the electrolytic cell to the cooling tunnel, the butts are placed in containers in which they can be covered with alumina in order to limit emissions of fluorine gas. This technical solution is not fully satisfactory because it requires a tunnel of considerable length, between 25 and 60 meters, requiring significant fluidization rates, as well as means for handling and moving the anodes which are potential source of failures. The tunnel also requires a relatively complex device for injecting air so as to also fluidize the alumina located above the butts. The passage of anode butts in connecting containers requires additional handling operations. In addition, as it is achieved, the covering of hot anodes with alumina can create a phenomenon of alumina geyser and requires emptying the alumina after each use of the container. The proposed invention makes it possible to limit the emissions of gaseous effluents by the anode butts after their removal from the electrolysis cells, and to capture the emanations produced by a simple device for implementation. It consists in particular, preferably for each anode butt removed from a tank, to isolate the portion of the butt covered with bath residues of the ambient air. For this, the butt is immersed in a volume of alumina powder contained in a tray so that the butt is completely immersed in the alumina. The fluorine gas that may be formed is immediately captured by the alumina, thus avoiding any pollution of the hall. Thus, the invention consists in a process for treating anode butts from aluminum production tanks by igneous electrolysis by covering the anode butts with alumina having a fluorine uptake capacity, characterized in that that, as soon as a butt is removed from an electrolytic cell, said butt is immersed in alumina previously fluidized to facilitate the immersion, and in that the fluidization of the alumina is stopped as soon as the end of immersing, so that the butt is covered, with static alumina until the end of its transfer from said electrolytic cell to a station equipped with at least one suction and fume treatment device , in particular a hot crushing station or a cooling station, so as to confine the butt and limit its emission of gaseous pollutants, especially fluorinated. According to the invention, said volume of alumina is fluidized to facilitate the introduction of the still hot anode butt in this volume. Fluidization is cut off as soon as the butt is in place. After stopping the fluidization, the alumina falls by gravity and covers the anode butt leading to confinement thereof. Alumina then acts as a physical barrier, limiting air convection movements around the butt, and chemical barrier since the gaseous fluoride emitted by the butt is immediately adsorbed by the alumina.
Avantageusement, l'alumine est fluidisée lors du retrait du mégot d'anode pour faciliter le retrait. Advantageously, the alumina is fluidized during removal of the anode butt to facilitate removal.
La partie carbonée est à une température d'environ 700 °C lorsque le mégot d'anode est retiré de la cuve d'électrolyse. A partir d'une température d'environ 300 °C, l'émission de gaz fluoré par la partie carbonée devient suffisamment faible pour qu'il ne soit plus nécessaire de la confiner. The carbon portion is at a temperature of about 700 ° C when the anode butt is removed from the electrolysis cell. From a temperature of about 300 ° C, the emission of fluorinated gas by the carbon portion becomes low enough that it is no longer necessary to confine it.
Après le transfert du mégot d'anode au poste de concassage à chaud équipé d'au moins un dispositif d'aspiration et de traitement des fumées, l'alumine est de nouveau fluidisée pour favoriser le retrait du mégot d'anode hors du volume d'alumine dans lequel ledit mégot a été confiné. La partie carbonée est concassée pour être utilisée pour la fabrication de nouvelles anodes. Après l'opération de concassage, les éléments carbonés sont maintenus sous au moins un dispositif d'aspiration et de traitement des fumées, au moins jusqu'à ce que leur température soit descendue en dessous de 300 °C. After transfer of the anode butt to the hot crushing station equipped with at least one suction and fume treatment device, the alumina is fluidized again to promote removal of the anode butt out of the volume of the anode. alumina wherein said butt has been confined. The carbonaceous part is crushed to be used for the manufacture of new anodes. After the crushing operation, the carbon elements are maintained under at least one suction and treatment device. fumes, at least until their temperature has dropped below 300 ° C.
Dans une variante avantageuse de l'invention, après le transfert du mégot d'anode au poste de refroidissement équipé d'au moins un dispositif d'aspiration et de traitement des fumées, l'alumine est de nouveau fluidisée pour favoriser le refroidissement de la partie carbonée du mégot d'anode. Le refroidissement est avantageusement maintenu jusqu'à ce que la température de la partie carbonée soit descendue en dessous de 300 °C. In an advantageous variant of the invention, after the transfer of the anode butt to the cooling station equipped with at least one suction and fume treatment device, the alumina is again fluidized to promote the cooling of the carbon part of the anode butt. Cooling is advantageously maintained until the temperature of the carbon portion has dropped below 300 ° C.
L'invention consiste également en un dispositif pour le traitement de mégots d'anode, permettant de mettre en œuvre le procédé décrit précédemment, caractérisé en ce qu'il comprend au moins un bac contenant de l'alumine en quantité suffisante pour recouvrir le mégot d'anode et un moyen de fluidisation de cette alumine. The invention also consists of a device for the treatment of anode butts, making it possible to implement the process described above, characterized in that it comprises at least one tank containing alumina in an amount sufficient to cover the butt anode and a fluidization means of this alumina.
L'invention consiste, mises à part les dispositions exposées ci-dessus, en un certain nombre d'autres dispositions dont il sera plus explicitement question ci-après à propos d'exemples de réalisation, décrits avec référence aux dessins annexés, mais qui ne sont nullement limitatifs. Sur ces dessins : The invention consists, apart from the arrangements described above, in a certain number of other arrangements which will be more explicitly discussed below with regard to exemplary embodiments, described with reference to the appended drawings, but which do not are in no way limiting. On these drawings:
- Fig.1 représente une vue schématique en perspective d'une anode consommée, - Fig. 2 représente une vue schématique en perspective d'un exemple de réalisation de réceptacle à mégots selon l'invention, - Fig.1 is a schematic perspective view of an anode consumed, - Fig. 2 is a diagrammatic perspective view of an exemplary embodiment of the butt receptacle according to the invention,
- Fig. 3 représente une vue schématique en coupe verticale d'un réceptacle à mégots selon l'invention, et, - Fig. 3 is a diagrammatic view in vertical section of a cigarette butt receptacle according to the invention, and
- Fig. 4 représente une vue schématique d'un réceptacle à mégots selon l'invention placé à un poste équipé d'un dispositif d'aspiration et de traitement des fumées. La figure 1 représente une vue schématique d'une anode simple consommée, standard pour la production d'aluminium par électrolyse ignée. Elle est composée d'une partie carbonée 1 accrochée à une tige métallique 2, longue de 2 à 3 m, et servant à l'alimentation en courant électrique et à la fixation à la cuve d'électrolyse. Lors de son retrait de la cuve d'électrolyse, une couche d'alumine de couverture résiduelle 1 2 reste au dessus de la partie carbonée 1 et recouvre une partie de la tige métallique 2. Le mégot d'anode 5 est donc composé de la partie carbonée 1 , de l'alumine de couverture résiduelle 1 2 et de la partie de la tige métallique 2 qui est recouverte par l'alumine de couverture résiduelle 1 2. Il existe également des anodes doubles composées de deux parties carbonées telles que 1 accrochées à une seule partie ou tige métallique 2. Selon l'exemple de réalisation de l'invention représenté en Fig. 2, les réceptacles 3 à mégots sont composés d'une structure métallique définissant des bacs 4a, 4b, 4c à l'intérieur desquels sont déposés les mégots d'anode 5. Dans cet exemple, le réceptacle 3 est composé de 3 bacs et peut donc accueillir trois mégots d'anode double tels que 5. Selon d'autres exemples de réalisation, les réceptacles 3 auront un nombre de bacs différent, par exemple 2 ou 4. - Fig. 4 is a schematic view of a cigarette butt receptacle according to the invention placed at a station equipped with a device for suction and treatment of fumes. Figure 1 shows a schematic view of a consumed simple anode, standard for the production of aluminum by igneous electrolysis. It is composed of a carbon part 1 hooked to a metal rod 2, 2 to 3 m long, and serving for the supply of electric current and the attachment to the electrolysis cell. Upon removal from the electrolytic cell, a layer of residual cover alumina 1 2 remains above the carbon portion 1 and covers a portion of the metal rod 2. The anode butt 5 is composed of the part 1, residual cover alumina 1 2 and part of the metal rod 2 which is covered by the residual cover alumina 1 2. There are also double anodes composed of two carbon parts such as 1 hung only one part or metal rod 2. According to the embodiment of the invention shown in FIG. 2, the receptacles 3 with butts are composed of a metal structure defining trays 4a, 4b, 4c inside which are deposited the anode butts 5. In this example, the receptacle 3 is composed of 3 trays and can therefore accommodate three double anode butts such as 5. According to other embodiments, the receptacles 3 will have a different number of bins, for example 2 or 4.
Le fond de chaque bac 4 comprend une plaque 6 d'un matériau permettant de retenir l'alumine 8 tout en ayant une porosité suffisante pour assurer le rôle de toile de fluidisation. Cette plaque 6 peut, par exemple, être un fritté métallique. Elle est supportée par des renforts non représentés sur cette figure. La zone 7 sous la plaque 6 de fritté métallique est alimentée en gaz de fluidisation afin d'assurer la fluidisation de l'alumine 8. Le gaz de fluidisation est avantageusement de l'air mais peut être d'une autre nature, par exemple de l'azote. The bottom of each tray 4 comprises a plate 6 of a material for retaining alumina 8 while having sufficient porosity to act as a fluidizing fabric. This plate 6 may, for example, be a metal sinter. It is supported by reinforcements not shown in this figure. The zone 7 under the metal sintered plate 6 is supplied with fluidization gas in order to ensure the fluidization of the alumina 8. The fluidization gas is advantageously air but may be of a different nature, for example nitrogen.
Le dispositif d'alimentation en gaz de fluidisation de la zone 7 n'est pas représenté sur les figures. La plaque 6 de fritté métallique et la charge d'alumine 8 génèrent une perte de charge qui favorise une répartition homogène du gaz sur toute la surface de la plaque 6 de fritté métallique. Néanmoins, selon le nombre de renforts de soutient de la plaque 6 de fritté métallique et leur géométrie, le dispositif d'alimentation en gaz de fluidisation peut comprendre plusieurs arrivées de gaz de sorte de répartir le débit sur différents secteurs de la surface de la zone 7. The fluidization gas supply device of zone 7 is not shown in the figures. The metal sintered plate 6 and the alumina filler 8 generate a pressure drop which promotes a homogeneous distribution of the gas over the entire surface of the metal sinter plate 6. Nevertheless, depending on the number of support reinforcements of the metal sintered plate 6 and their geometry, the fluidization gas supply device may comprise several gas flows so as to distribute the flow rate over different sectors of the surface of the zone. 7.
Sur la Fig. 2, sont représentées les trois situations dans lesquelles peut se trouver un bac 4. Ainsi, le bac 4a est vide, sans alumine, le bac 4b est rempli d'alumine fluidisée 8a et le bac 4c contient un mégot d'anode 5 confiné dans un volume d'alumine non fluidisée 8b. En production, l'ensemble des bacs 4 est rempli d'alumine 8. In FIG. 2, are shown the three situations in which a tray 4 may be. Thus, the tray 4a is empty, without alumina, the tray 4b is filled with fluidized alumina 8a and the tray 4c contains an anode butt 5 confined in a volume of non-fluidized alumina 8b. In production, all the tanks 4 is filled with alumina 8.
La fluidisation de l'alumine 8 est avantageusement pilotée individuellement, bac 4 par bac, de sorte de limiter cet état au bac 4 où la fluidisation est nécessaire. The fluidization of the alumina 8 is advantageously controlled individually, tray 4 per tray, so as to limit this state to the tray 4 where the fluidization is necessary.
Il est avantageux de conserver une épaisseur minimale d'alumine 8 sous le mégot d'anode 5 et d'éviter que les mégots 5 ne viennent en contact contre la plaque 6 de fritté métallique. Selon l'exemple de réalisation de la Fig. 3, deux traverses 9 servent de buttées ou d'entretoises entre le mégot d'anode 5 et la plaque 6. Les traverses 9 sont placées à quelques centimètres au-dessus de la plaque de fritté métallique 6, par exemple 1 0 cm. Le nombre, la forme et les dimensions de ces traverses 9 sont choisies de sorte de ne pas augmenter les pertes de charges pour le gaz de fluidisation et de permettre un accès aux opérateurs pour les opérations de vidange et de nettoyage des bacs 4. Par exemple, les traverses 9 peuvent être réalisées en profilé en I ou en T. Les traverses 9 sont par exemple fixées par leurs extrémités longitudinales sur deux parois verticales opposées de la structure métallique 3. Elles peuvent également reposer sur la plaque 6 si une reprise de charge est prévue en dessous de la plaque 6. It is advantageous to maintain a minimum thickness of alumina 8 under the anode butt 5 and to prevent the butts 5 from coming into contact with the metal sinter plate 6. According to the embodiment of FIG. 3, two crosspieces 9 serve as abutments or spacers between the anode butt 5 and the plate 6. The crosspieces 9 are placed a few centimeters above the metal sintered plate 6, for example 1 0 cm. The number, shape and dimensions of these sleepers 9 are chosen so as not to increase the pressure drops for the fluidizing gas and to allow access to the operators for the emptying and cleaning operations of the bins 4. For example the sleepers 9 may be made of I-beam or T-shaped section. The sleepers 9 are for example fixed by their longitudinal ends on two opposite vertical walls of the metal structure 3. They may also rest on the plate 6 if a load recovery is provided below the plate 6.
Comme représenté en Fig. 2 et Fig. 3, la tige 2 d'anode peut être stabilisée au moyen d'attaches amovibles 1 0. Celles-ci sont par exemple fixées entre le bord de la structure métallique 3 et la tige 2 de l'anode. As shown in FIG. 2 and FIG. 3, the anode rod 2 can be stabilized by means of removable fasteners 1 0. These are for example fixed between the edge of the metal structure 3 and the rod 2 of the anode.
Pour un mégot d'anode 5 d'environ 0,3 m3, la quantité d'alumine 8 nécessaire par bacs 4 est d'environ 1 ,8 m3. Les dimensions des bacs 4 sont définies par les dimensions de la partie carbonée 1 des mégots 5 et le volume d'alumine 8 nécessaire. Les bacs 4 ont par exemple une longueur de 2 m, une largeur de 2 m pour une hauteur de 1 m. La hauteur d'alumine 8 avant l'immersion du mégot est d'environ 0,6 m. For anode butt 5 of about 0.3 m 3 , the amount of alumina 8 needed per tray 4 is about 1.8 m 3 . The dimensions of the tanks 4 are defined by the dimensions of the carbon portion 1 of the butts 5 and the volume of alumina 8 required. The bins 4 have for example a length of 2 m, a width of 2 m and a height of 1 m. The height of alumina 8 before immersion of the butt is about 0.6 m.
L'alimentation des bacs 4 en gaz de fluidisation peut être réalisée par différents moyens, par exemple en se connectant sur le réseau d'air de fluidisation des cuves d'électrolyse. Un réseau spécifique d'air peut également être réalisé pour la fluidisation des bacs 4 pour l'ensemble du potroom. Selon une autre variante, chaque réceptacle 3 peut être équipé d'un ventilateur délivrant le débit d'air nécessaire au réceptacle. Le débit et la pression d'alimentation de l'air de fluidisation de l'alumine sont ajustés lors de la mise en service de l'installation. Par exemple, un bac 4 est alimenté avec un débit d'environ 270 m3/h sous une pression d'environ 1 500 daPa. The feed of the tanks 4 in fluidization gas can be carried out by various means, for example by connecting to the fluidization air network of the electrolysis tanks. A specific air network can also be realized for the fluidization of the bins 4 for the entire potroom. According to another variant, each receptacle 3 can be equipped a fan delivering the necessary air flow to the receptacle. The flow rate and supply pressure of the alumina fluidization air are adjusted during commissioning of the plant. For example, a tank 4 is fed with a flow rate of about 270 m 3 / h under a pressure of about 1500 daPa.
L'alumine 8 utilisée n'a pas besoin d'avoir un pouvoir de captation très élevé. Elle sert principalement de barrière physique pour empêcher la convection de l'air autour de l'anode. Ainsi, de l'alumine 8 fluorée utilisée dans les cuves d'électrolyse peut être utilisée dans les bacs 4. En variante, de l'alumine 8 pure, non fluorée, peut être utilisée. The alumina 8 used does not need to have a very high capture power. It serves primarily as a physical barrier to prevent convection of air around the anode. Thus, fluorinated alumina 8 used in the electrolytic tanks can be used in the tanks 4. Alternatively, pure, non-fluorinated alumina 8 can be used.
Lors du retrait du mégot 5 du bac 4, un tas d'alumine peut rester en place sur le dessus de la partie carbonée 1 . Une partie de cette alumine est susceptible de tomber sur le sol lors du déplacement du mégot 5. Pour éviter cela, après avoir levé le mégot 5 au dessus du lit d'alumine, l'opérateur peut chasser cette alumine au moyen d'un outil manuel ou d'un jet de gaz. Selon une variante de réalisation, des buses latérales peuvent être placées en partie supérieure du bac 4 pour réaliser cette opération automatiquement lors du retrait du mégot 5. When removing the butt 5 from the tray 4, a pile of alumina can remain in place on top of the carbonaceous part 1. Part of this alumina is likely to fall on the ground during the displacement of the butt 5. To avoid this, after lifting the butt 5 above the bed of alumina, the operator can hunt this alumina by means of a tool manual or a gas jet. According to an alternative embodiment, lateral nozzles may be placed in the upper part of the tray 4 to carry out this operation automatically during removal of the butt 5.
Pour rendre la manutention plus aisée, les réceptacles 3 à mégots comprennent des moyens permettant d'être pris en charge par exemple par un véhicule à fourches ou par un pont roulant. Ainsi, après la mise en place des mégots 5 dans les bacs 4, il est possible de déplacer les réceptacles 3 dans un espace situé au voisinage de la potroom, dans lequel sera réalisé par exemple le refroidissement des mégots 5 ou leur concassage. To make handling easier, the receptacles 3 butts include means to be supported for example by a forked vehicle or a crane. Thus, after the placement of the butts 5 in the bins 4, it is possible to move the receptacles 3 in a space in the vicinity of the potroom, in which will be performed for example the cooling of the butts 5 or crushing them.
Généralement, une potroom comprend 1 ou 2 rangées parallèles de cuves d'électrolyse. Les opérations de remplacement des anodes sont réalisées le long des potroom. Il convient donc de placer un réceptacle 3 comprenant trois bacs 4 à mégots 5 toutes les trois cuves sur toute rangée au même moment que sont disposées les anodes neuves prêt des cuves. Ainsi, pour une halle d'électrolyse contenant une centaine de cuves, une trentaine de réceptacles 3 à mégot sont suffisants. Generally, a potroom includes 1 or 2 parallel rows of electrolysis tanks. The anode replacement operations are carried out along the potroom. It is therefore appropriate to place a receptacle 3 comprising three trays 4 butts 5 every three tanks in any row at the same time as are disposed the new anodes ready tanks. Thus, for an electrolysis hall containing one hundred vats, about thirty receptacles 3 with butts are sufficient.
Il est nécessaire de renouveler périodiquement l'alumine 8 contenue dans les bacs 4 de sorte à conserver un pouvoir de captation suffisant. La fluidisation de l'alumine 8 à chaque opération de dépose et de retrait de mégot 5 permet d'assurer un brassage de l'alumine 8 et donc un enrichissement en fluor homogène de l'ensemble du bac 4. La fréquence de vidange est liée à la qualité d'alumine utilisée. Plus le pouvoir de captation initial de l'alumine 8 sera important et plus les vidanges pourront être espacées. Ainsi, l'usage d'alumine pure, non fluorée, à la place de l'alumine destinée aux cuves permet de renouveler moins fréquemment les bacs 4. Il est avantageux d'organiser une vidange périodique à une fréquence définie ou à l'occasion de l'évacuation des déchets de bain d'électrolyse. La vidange des bacs 4 sera avantageusement réalisée après le transfert des réceptacles 3 vers un espace approprié. It is necessary to periodically renew the alumina 8 contained in the tanks 4 so as to maintain sufficient captation capacity. The fluidization of alumina 8 at each removal and removal operation of butt 5 makes it possible to ensure mixing of the alumina 8 and thus a homogeneous fluorine enrichment of the whole of the tank 4. The emptying frequency is linked to the quality of alumina used. The higher the initial capture capacity of alumina 8 will be important and more emptied can be spaced. Thus, the use of pure, non-fluorinated alumina in place of the alumina intended for the tanks makes it possible to renew the tanks 4 less frequently. It is advantageous to organize a periodic emptying at a defined frequency or occasionally the evacuation of electrolysis bath waste. The emptying of the tanks 4 will advantageously be performed after the transfer of the receptacles 3 to a suitable space.
Chaque bac 4 du dispositif selon l'invention comprend une ou plusieurs trappes de vidange placées juste au dessus de la plaque 6 de fritté métallique. Il est avantageux de fluidiser l'alumine lors de la vidange de sorte à faciliter son évacuation. La plaque ou toile de fluidisation 6 est suffisamment solide pour qu'un opérateur puisse entrer dans le réceptacle 3 à mégot enlever les fragments de mégots 5 d'anode tombés sur le fond. Each tank 4 of the device according to the invention comprises one or more emptying hatches placed just above the metal sinter plate 6. It is advantageous to fluidize the alumina during the emptying so as to facilitate its evacuation. The fluidizing plate or fabric 6 is strong enough for an operator to enter the butt receptacle 3 to remove anode butt fragments fallen on the bottom.
Sur la Fig. 4 est représenté schématiquement un réceptacle 3 à mégots 5 selon l'invention, placé à un poste 1 1 équipé de dispositifs 13 d'aspiration et de traitement des fumées. Ce poste 1 1 peut être notamment un poste de concassage à chaud ou un poste de refroidissement des mégots d'anode 5. In FIG. 4 is schematically represented a receptacle 3 with butts 5 according to the invention, placed at a station 1 1 equipped with devices 13 for suction and treatment of fumes. This station 11 may be in particular a hot crushing station or an anode butt cooling station 5.

Claims

REVENDICATIONS
1 . Procédé de traitement de mégots d'anode (5) provenant de cuves de production d'aluminium par électrolyse ignée, en recouvrant les mégots d'anode (5) par de l'alumine ayant un pouvoir de captation du fluor, caractérisé en ce que, dès le retrait d'un mégot (5) d'une cuve d'électrolyse, ledit mégot d'anode (5) est immergé dans de l'alumine (8) préalablement fluidisée pour faciliter l'immersion, et en ce que la fluidisation de l'alumine (8) est stoppée dès la fin de l'immersion, de sorte que le mégot d'anode (5) soit recouvert par de l'alumine statique jusqu'à la fin de son transfert de ladite cuve d'électrolyse à un poste (1 1 ) équipé d'au moins un dispositif d'aspiration et de traitement des fumées (1 3), notamment un poste de concassage à chaud ou un poste de refroidissement, de sorte à confiner le mégot d'anode (5) et limiter son émission de polluants gazeux, notamment fluorés. 1. Process for the treatment of anode butts (5) from aluminum production tanks by igneous electrolysis, covering the anode butts (5) with alumina having a fluorine uptake capacity, characterized in that after removing a butt (5) from an electrolytic cell, said anode butt (5) is immersed in alumina (8) previously fluidized to facilitate immersion, and in that the fluidization of the alumina (8) is stopped at the end of the immersion, so that the anode butt (5) is covered by static alumina until the end of its transfer from said tank of electrolysis at a station (1 1) equipped with at least one suction and fume treatment device (1 3), in particular a hot crushing station or a cooling station, so as to confine the anode butt (5) and limit its emission of gaseous pollutants, especially fluorinated.
2. Procédé selon la revendication 1 , caractérisé en ce que, ledit mégot d'anode (5) étant en place audit poste (1 1 ), équipé d'au moins un dispositif d'aspiration et de traitement des fumées (1 3), l'alumine (8) est fluidisée pour favoriser le refroidissement de la partie carbonée dudit mégot (5). 2. Method according to claim 1, characterized in that said anode butt (5) being in place at said station (1 1), equipped with at least one suction and fume treatment device (1 3). the alumina (8) is fluidized to promote cooling of the carbon portion of said butt (5).
3. Procédé selon la revendication 2, caractérisé en ce que le refroidissement de la partie carbonée dudit mégot (5) favorisé par l'alumine (8) fluidisée est maintenu jusqu'à ce que la température de la dite partie carbonée soit descendue en dessous de 300 °C. 3. Method according to claim 2, characterized in that the cooling of the carbon portion of said butt (5) favored by the fluidized alumina (8) is maintained until the temperature of said carbon portion is lowered below 300 ° C.
4. Procédé selon l'une quelconques des revendications 1 à 3, caractérisé en ce que l'alumine (8) est fluidisée lors du retrait du mégot d'anode (5). 4. Method according to any one of claims 1 to 3, characterized in that the alumina (8) is fluidized during removal of the anode butt (5).
5. Dispositif pour le traitement de mégots d'anode, permettant de mettre en œuvre le procédé selon l'une des revendications 1 à 4, caractérisé en ce qu'il comprend au moins un bac (4) contenant de l'alumine (8) en quantité suffisante pour recouvrir le mégot d'anode (5) et un moyen de fluidisation de cette alumine (8). 5. Device for the treatment of anode butts, for implementing the method according to one of claims 1 to 4, characterized in that it comprises at least one tray (4) containing alumina (8). ) in sufficient quantity to cover the anode butt (5) and a fluidization means of this alumina (8).
6. Dispositif selon la revendication 5, caractérisé en ce qu'il comprend au moins un réceptacle (3) à mégot, en une structure métallique, définissant au moins un bac (4), et de préférence plusieurs bacs adjacents (4a, 4b, 4c), pouvant chacun accueillir au moins un mégot d'anode (5). 6. Device according to claim 5, characterized in that it comprises at least one receptacle (3) butt, in a metal structure, defining at least one tank (4), and preferably several adjacent tanks (4a, 4b, 4c), each of which can accommodate at least one anode butt (5).
7. Dispositif selon la revendication 6, caractérisé en ce que le fond de chaque bac (4) comprend une plaque (6) d'un matériau permettant de retenir l'alumine (8) tout en ayant une porosité suffisante pour assurer le rôle de toile de fluidisation, une zone (7) sous la plaque (6) étant alimentée en gaz de fluidisation, tel que de l'air. 7. Device according to claim 6, characterized in that the bottom of each tray (4) comprises a plate (6) of a material for retaining the alumina (8) while having sufficient porosity to perform the role of fluidization fabric, an area (7) under the plate (6) being supplied with fluidizing gas, such as air.
8. Dispositif selon la revendication 7, caractérisé en ce que ladite plaque (6) est en un matériau fritté métallique. 8. Device according to claim 7, characterized in that said plate (6) is of a metal sintered material.
9. Dispositif selon l'une quelconque des revendications 5 à 8, caractérisé en ce que chaque bac est équipé de traverses (9) servant de butée sur laquelle vient reposer un mégot d'anode (5) immergé dans ledit bac (4) pour éviter que ledit mégot (5) ne vienne en contact avec le fond dudit bac (4) et conserver une épaisseur d'alumine (8) sous ledit mégot d'anode (5). 9. Device according to any one of claims 5 to 8, characterized in that each tray is equipped with crosspieces (9) serving as an abutment on which rests an anode butt (5) immersed in said tray (4) for preventing said butt (5) from coming into contact with the bottom of said tank (4) and keeping a thickness of alumina (8) under said anode butt (5).
10. Dispositif selon l'une quelconque des revendications 5 à 9, caractérisé en ce qu'il comprend de plus des attaches amovibles (10) fixées entre la tige (2) d'un mégot d'anode (5) et un bord d'un bac (4) permettant de stabiliser ledit mégot d'anode (5) immergé dans ledit bac (4). 10. Device according to any one of claims 5 to 9, characterized in that it further comprises removable fasteners (10) fixed between the rod (2) of an anode butt (5) and an edge of a tray (4) for stabilizing said anode butt (5) immersed in said tray (4).
PCT/FR2012/051014 2011-05-16 2012-05-09 Process and device for limiting the emission of gaseous pollutants from anode butts WO2012156616A1 (en)

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CN201280021816.1A CN103597125B (en) 2011-05-16 2012-05-09 The method of discharging for the gas pollutant limited from anode scrap and equipment thereof

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EP2710170A1 (en) 2014-03-26
FR2975405A1 (en) 2012-11-23
FR2975405B1 (en) 2013-05-17
CA2835800C (en) 2019-07-02
CN103597125B (en) 2016-04-27
EP2710170B1 (en) 2017-01-18
CA2835800A1 (en) 2012-11-22
CN103597125A (en) 2014-02-19

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